Subtract 5/45 from 30/21, Solve 1 9/21

Subtract 5/45 from 30/21

1^st number: 1 9/21, 2^nd number: 5/45

30/21 - 5/45 is 83/63.

Find the least common denominator or LCM of the two denominators:
LCM of 21 and 45 is 315

Next, find the equivalent fraction of both fractional numbers with denominator 315
For the 1st fraction, since 21 × 15 = 315,
30/21 = 30 × 15/21 × 15 = 450/315
Likewise, for the 2nd fraction, since 45 × 7 = 315,
5/45 = 5 × 7/45 × 7 = 35/315
Subtract the two like fractions:
450/315 - 35/315 = 450 - 35/315 = 415/315
After reducing the fraction, the answer is 83/63
In mixed form: 120/63

MathStep (Works offline)

Download our mobile app and learn to work with fractions in your own time:
Android and iPhone/ iPad